Hazardous wastes are not something new that businesses are dealing with; however, the number of different hazardous wastes combined with the volume of hazardous wastes continues to increase exponentially. This increase in hazardous wastes is especially prevalent in the medical profession where hospitals, clinics, medical schools, veterinary schools and hospitals and doctors' offices dispose of tons of biological and/or hazardous wastes each year. These wastes must either be bagged, sealed and transported offsite for disposal or treated onsite. If they are transported offsite, then the medical facility may be responsible if the wastes end up in the water system or in a landfill where the landfill is not adequately secured for runoff or trespassers.
There are a number of patent and patent applications that attempt to address these problems. For example, U.S. Pat. No. 4,178,239 issued to Lowther discloses a system of treating aqueous sewage that contains both biodegradable materials and non-biodegradable materials by a series of processing steps that includes ozone pretreatment, oxygenation treatment in the presence of aerobic or facultative anaerobic microorganisms and another ozone treatment. This treatment process is not only complicated, but also does not allow for the treatment of significant solids in the waste. In fact, all of the solids are skimmed or filtered off in order to leave the sludge for treatment. The process is similar in U.S. Pat. No. 7,384,555 issued to Yasui et al. where solids are removed from a sludge waste material before treatment.
U.S. Pat. No. 5,077,007 issued to Pearson discloses a batch treatment process and related apparatus for disinfection of infectious waste. According to Pearson, hazardous wastes are put through at least one shredder to significantly reduce the size of the waste material. This design is problematic, because it introduces several shredders to the processing line if the waste materials are larger than those which can be accommodated by the primary shredder. All hazardous wastes cannot be accommodated by one shredder, according to Pearson.
Another design shortcoming in Pearson is the fluidized bed reactor vessel with diffusers, such as fine bubble diffusers or stone diffusers, at the bottom of the vessel. These types of diffusers cannot generate the material turn over that is required to adequately agitate the waste material. For example, the waste material usually has a high volume of plastic that floats in the solution. This material will not be completely turned over and mixed with the solution to provide adequate contact with the solution. In addition, by pumping air thru the product, you force the sanitizing chemistry, which is in the fluid solution, out into the gas space above the fluid and this lowers the concentration in the fluid, reducing its sanitizing capacity. If the waste material has been shredded enough to be fine and have a large surface area, then it is likely that these diffusers are going to become clogged with the waste materials if the concentration of solid waste materials exceeds more than a few percent of the total solution.
The Pearson design contemplates that the waste material is primarily water or liquid waste and a smaller percentage of waste solids. In addition, Pearson discloses that water is included initially in the bed reactor before the hazardous wastes are added for processing. This design is problematic for several reasons. First, it will obviously lead to more down time for the apparatus if there are more solids in the waste material. Second, if the user/operator can control the waste material to keep the percentage of solids lower, then it is likely that it will take longer to process waste materials, since most hazardous medical wastes are solid materials.
U.S. Pat. No. 5,116,574 issued to Pearson discloses a continuous treatment process and related apparatus for disinfecting infectious waste materials, which is different from the '007 Pearson patent by the introduction of the concept of continuous treatment. The same problems exist in this patent, in that it introduces several shredders to the processing line if the waste materials are larger than those which can be accommodated by the primary shredder. All hazardous wastes cannot be accommodated by one shredder, according to Pearson. While the Pearson process is continuous, the design is such that the waste material is primarily water or liquid waste and a smaller percentage of waste solids. This design is problematic for several reasons. First, it will obviously lead to more down time for the apparatus if there are more solids in the waste material. Second, if the user/operator can control the waste material to keep the percentage of solids lower, then it is likely that it will take longer to process waste materials, since most hazardous medical wastes are solid materials.
U.S. Pat. No. 5,820,541 issued to Berlanga Barrera discloses a treatment method for sterilization of biological, solid, liquid, ferrous metallic, non-ferrous metallic, toxic and “dangerous” hospital waste material. Upon review of this process, there are still additional pre-treatment and treatment steps that add to the complexity of the process. For example, the original waste materials are milled to break them down into smaller pieces and then the milled material is rinsed and treated with water before being centrifuged. This process is designed to bathe the residues “and dissolving the blood, semisolid, purulents, human body parts, etc., so as to be in good condition to receive the treatment that, with the formulation of compressed air, ozone, carbon dioxide, these gasses being combined by an ozone generator apparatus.” The treatment of the washed and centrifuged materials is then performed followed by another centrifuge. Each of the steps of the process is conducted in an aqueous environment, except for the milling step.
U.S. patent application Ser. Nos. 11/930795, 11/568352, 11/212009 and 11/190343 are commonly-owned by TriNova™ and are incorporated herein by reference in their entirety. These applications disclose a hospital waste treatment apparatus and process that advances the field of waste treatment, but is still inadequate for large loads of medical and other hazardous wastes. The shredder is designed to accommodate large loads; however, once the materials enter the processing system comprising the pump, they can easily clog the system resulting in operational shutdowns and failures. In addition, there is no description or ability to process various wastes in different batches, as may be required if some wastes are relatively easy to disinfect and some are not. Finally, the systems disclosed are not designed to accommodate different disinfectant systems, such as gas, gas/liquid mixtures and/or liquid mixtures.
It would be ideal if a hazardous waste sanitation and removal device and system could easily prepare any type of hazardous waste for sanitation and disinfection, while at the same time actively monitoring the effectiveness and rate of sanitation. In addition, it would be ideal to develop such a system that reduces buildup and solids fall-out in the system, can be batch or continuous, can segregate and actively sanitize difficult or complex waste materials, and can be used with a gas, liquid and/or liquid/gas system.